TNL-4366
Changes in studio to allow the hide_after_due setting to be utilized.

Includes:
    -python changes to contentstore, where the data is stored.
    -refactoring of timed-examination-preference-editor.underscore, to add this
        setting and make the editor more accessible.
    -javascript changes to link the new setting to the correct data model.
    -sass updates to fix a11y issues on the editor modal.
    -addition of post-due visibility information to course outline in studio.
    -new tests: python, js, acceptance, and a11y

TNL-4366
Changes in studio to allow the hide_after_due setting to be utilized.

Includes:
    -python changes to contentstore, where the data is stored.
    -refactoring of timed-examination-preference-editor.underscore, to add this
        setting and make the editor more accessible.
    -javascript changes to link the new setting to the correct data model.
    -sass updates to fix a11y issues on the editor modal.
    -addition of post-due visibility information to course outline in studio.
    -new tests: python, js, acceptance, and a11y

Use new best practices.

- added the new field review_rules for software secure
- added a new tab name "Additional Settings" for the proctored/timed exams

It turns out that loading JavaScript with $.getScript
causes Chrome to treat the file as an XHR request
and not JS. I've switched over to using RequireJS
to load the URL which already has the ability to
dynamically load files and have the browser
recognize them.

added unit tests and fixed JS tests

added bok choy tests

fixed broken botchoy tests

fixed course discovery broken test

removed monkey patch at class level

changes after feedback from matte

which shows a notification if there are any "Queued" or "Uploading" videos still in progress.

Make escaping for json simpler and more consistent in Mako templates
- add escape_json_dumps to escape and json.dumps
- add escape_js_str to escape javascript string
- refactor Studio to use escape_json_dumps in Mako templates

TNL-2646: Escape json.dumps

I've changed the logic so that AjaxHelpers keeps
track of which requests have not yet had mock
responses sent. This ensures that every response
is handled before moving on to the next one,
rather than always handling the last request.
My intention is that this won't allow bugs to creep
in where a request isn't fired and instead the test
responds to an old request. It also should ensure
that extra events aren't accidentally fired.

TNL-3166

TNL-2689